The present invention relates generally to the field of gripping, transporting, loading and unloading objects such as cylindrical containers for fluids, and specifically to a device that is capable of loading and unloading empty, partially filled, or completely filled, water bottles. Water bottles come in a variety of sizes. Those commonly used for drinking water include three (3), four (4) and five (5) gallon bottles. However, it is to be understood that the present invention could be used with any size container or bottle. Large water bottles, and especially those that are filled or partially filled, are difficult to pick up, hold and transport, due to their unique cylindrical shape and weight. Often, there is typically a requirement of not marring the exterior surface of each bottle during loading and unloading. Moreover, drinking water bottles are often recycled and refilled. Filled bottles are loaded into racks for storage and transport to customers. The same racks are returned to the water processing facility with empty bottles. The empty bottles must be removed from each rack before filled bottles are reloaded.
At the end of a water processing conveyor line, water bottles often arrive filled with specially filtered or processed water. While each cylindrical, bottle-shaped, container serves the primary purpose of confining the water or other fluid during shipping, the container may also serve the function of identifying the product through the use of trademarks or other product information applied directly on the container. On more elaborately printed water bottles, there may appear indicia advertising the product or its benefits. Three, four, and five gallon water bottles are commonly placed on top of a water cooler or water-dispensing device. These devices are often found in offices, homes and other highly visible areas. Therefore the container must be aesthetically attractive and visually appealing. Accordingly, it is of utmost importance that each container, and especially its product indicia, not be damaged or scuffed during removal from the conveyor line and loading for shipment. It is also important that the empty bottles returned for re-filling be treated with similar care.
In most instances the tasks of removing empty containers from the racks and loading full containers from a conveyor into the racks for storage or shipping have been carried out manually. While having some advantages, such as insuring that the containers are not damaged, manually handling containers is relatively a strenuous and tedious task. The continued lifting and moving of multiple, heavy filled containers can cause workers to strain and injure their backs. Further, depending upon the output speed and configuration of the conveyor line, many workers may be required to remove and properly load the filled containers. In an effort to reduce workforce size and injury costs, there has been a significant move toward automating this process by utilizing robots.
As is known in the art, industrial robots may be fitted with various grasping devices, known as xe2x80x9cend-effectorsxe2x80x9d or xe2x80x9cend of arm toolsxe2x80x9d (EOATs). Such devices may be utilized for the automated gripping and transporting of objects, including containers.
Most drinking water containers are cylindrical in shape and include a top, a neck, a cylindrical sidewall, and a bottom. Near the end of the water processing conveyor line, a cap is placed over the top and partially around the neck to seal the fluid within the container. Provided that the cap has been properly sealed to the container, the water will not leak, even if the container is partially or fully inverted.
Many end-effectors are commercially available for grasping various containers from a conveyor line and transporting them to another area. For example, a container may be removed from a conveyor line by one or more suction cups that temporarily adhere to the container. Alternatively, a pair of mechanical arms may apply a predetermined amount of pressure to the sidewalls of the container such that the container may be lifted and transported. It is even conceivable that a bladder could be placed around the container and then inflated to grasp the container for transport.
However, if a water bottle to be transported from a conveyor line to another station is relatively heavy (i.e. filled with a fluid, such as water), its unique geometrical shape combined with its weight makes it difficult to grasp. Suction cups cannot be readily attached to a heavy container having a unique geometry including cylindrical outer walls. Similarly, a number of mechanical arms applying a sufficient amount of pressure against the sidewall of the cylindrical container would most likely collapse or crush the container before the exerted force was great enough to lift and transport the filled container. Inflating and deflating a bladder is too time consuming and would not keep up with the rate at which filled containers arrive at the conveyor line end.
Another factor that controls the choice of device employed for removing bottle-shaped containers from a conveyor line and transferring them to a storage rack (or vice versa) is the consistency of container size. If each container coming off the conveyor line has the same physical size, the robotic end-effector can be designed specifically for that specific container size. However, if the container size varies, the end-effector must be capable of being readily adjustable to accommodate various container sizes.
Another factor that often dictates the means utilized for removing containers from conveyor lines and transporting them to storage racks is the amount of space available at the end of the conveyor line for this operation. Often times there is very little space allocated at the end of the conveyor line for removing containers. If a robot and robotic end-effector are to be utilized, the system must be sufficiently compact to allow for installation and operation within the allotted space available for such a device.
When filled water bottles are transported on a conveyor, they are typically moved in their upright position. The bottom or base of the bottle rests on the conveyor belt and the neck and bottle opening extend upwardly. However, the racks that are utilized for storage and transportation of water bottles hold the bottles in a horizontal orientation. Accordingly, the present invention must be capable of gripping each fall bottle and rotating the bottle from a generally vertical position to a generally horizontal position before inserting the bottle into the rack.
Accordingly, there is a need for a device that may be used for the gripping, transportation and placement of heavy and light cylindrical containers between two stations such as a conveyor line and a storage rack in an efficient manner. There is also a need for a device capable of easily gripping and rotating the cylindrical containers without damage. More specifically, there is a need for a device that is compact enough to be positionable and operationable at the end of a conveyor line. Furthermore, the device must be able to appropriately rotate the containers from their upright position to a horizontal position between the conveyor line and storage racks.
According to the present invention, the foregoing and other objects and advantages are attained by providing an apparatus which may be used in a confined environment to efficiently grasp and transport cylindrical objects of various sizes and weights between a pick-up position, such as the end of a conveyor line and a storage rack. The apparatus may also be used to grasp cylindrical objects from a storage rack and transport each object onto a pallet, into a case, or onto another conveyor line. In addition to grasping each object, the apparatus is capable of supportably rotating some objects through three hundred sixty (360) degrees of rotation and others through ninety (90) degrees of rotation in various planes.
A further object of the present invention is to provide an end-effector for an industrial robot, the end-effector being capable of picking up one or more cylindrical containers from a pick-up position and transporting the containers to a rack for storage or shipping. At the same time, additional cylindrical containers may be removed from the same rack and transported to the original pick-up position or another position.
A further object of the invention is to provide an end-effector that is capable of securely grasping each cylindrical object or container, whether empty or full, while not damaging or marring its outer surface.
In accordance with another aspect of the invention, the device can be utilized in a relatively confined area, as it requires a minimum amount of space around the periphery of the cylindrical container for gripping and loading or unloading the container.
A further advantage of the invention is to provide an end-effector for use with a robot that is easily adjustable to grip cylindrical containers of various sizes.
A further advantage of the invention is to provide a robotic end-effector that is capable of gripping more than one cylindrical container from a pick up position and transporting a group of containers to a separate location. The invention is similarly capable of gripping more than one cylindrical container from a rack and transporting said group to another location.
These and other objects and advantages are achieved in a system designed to unload empty and load filled, three, four, and five gallon water bottles into rack assemblies. Empty rack assemblies are loaded into a rack conveyor by a loading mechanism, such as a fork lift truck. The racks are next positively located for robotic loading.
Filled water bottles are conveyed into the robotic cell on the infeed conveyor. To avoid excessive backpressure, a stop mechanism allows only a predetermined number of bottles to enter the robotic pickup location. A product locator is advanced, around and between each bottle, creating the proper spacing to coincide with the rack being loaded. The robotic gripper assembly has also been adjusted to have the same spacing between the gripper mechanisms. When the bottles have been metered into position, and properly located, a conventional programmable logic controller (PLC) or similar device connected to the conveyor system signals the robot controller or control system for the robot that the bottles are ready for pickup.
Racks of empty bottles are conveyed into the robotic cell on the rack infeed conveyor. A rack is conveyed into the loading position, and positively positioned and held for robotic loading. When the rack has been positioned, the PLC signals the robot control system that a rack is ready for unloading and loading. The robot proceeds to unload empty bottles from the rack, and simultaneously, load full bottles into the rack.
The end-effector handles the same number of full bottles and empty bottles per robot cycle. Each gripper mechanism on the end-effector includes a plurality of fingers capable of moving between an open and a closed position around the bottleneck. The gripper mechanisms engage and grip around each bottleneck. In conjunction with each gripper mechanism, a pair of support pins is provided. The support pins run parallel with the longitudinal axis of each gripper mechanism. As the robot lifts the filled bottles from the conveyor, the robot wrist or fifth axis tilts upward, rotating the bottom of the bottle upwards. The support pins carry the weight of the filled bottle.
In a preferred embodiment, the invention may be described as an apparatus for gripping, transporting and loading or unloading a container capable of holding fluid, the apparatus having a pair of parallel rails spaced a predetermined distance from one another; a plurality of gripper mechanisms, each gripper mechanism being affixed to one of the rails; each gripper mechanism having a plurality of fingers, said finger having distal ends and each said finger being capable of moving from an open position to a clamped position; and each finger having a clamp plate attached to its distal end. In addition, the apparatus may include a number of support pins attached to each rail for supporting the containers,
In another preferred embodiment, the present invention is a robotic end-effector for an industrial robot, said robotic end-effector having a plate capable of being coupled to the robot, the plate including a pair of rails spaced laterally on said plate; a plurality of gripper mechanisms attached to each rail; each gripper mechanism having a number of fingers, said fingers capable of moving from an open position to a closed position.
In addition, the invention may be described as a system for gripping, transferring and loading or unloading fluid containers from a pick up position, the system comprising a supply of full containers at the pick up position; a rack, the rack filled with empty containers, a robot with an end-effector, the end-effector having a plurality of gripper mechanisms attached thereto; and an unloading station adjacent said pick up position whereby said end-effector simultaneously removes empty containers from said rack and loads full containers into said rack.
The present invention may also be described as a method for unloading empty containers and loading full containers into a rack, the method including the steps of removing an empty container from a group of empty containers in the rack, transferring said empty container to a drop off station, substantially simultaneously releasing said empty container while gripping a full container from a pick up station, transferring said full container to said rack, and loading said full container in said rack.